Shock absorbers for railway cars



May-2, 1961 H. w. MULCAHY ET AL 2,932,426

suocx ABSORBERS FOR RAILWAY CARS Filed May 18, 1959 2 Sheets-Sheet 2 InVen tors: Harry mNuIcahy Vernqn 6'.DanieIs0n By. WQWA SHOCK ABSORBERS non RAILWAY CARS Harry W. Mulcahy and Vernon S. Danielson, Chicago Heights, Ill., assignors to W. H. Miner, Inc., Chicago, 111., a corporation of Delaware Filed May 18, 1959, Ser. No. 813,849

5 Claims. (Cl. 213-221) This invention relates to shock absorbers for railway cars and particularly to mechanisms of the buffer type comprising a casing containing friction and resilient elements and embraced by a telescopically movable sleeve or buffer head.

The present invention provides a buffer having an initial soft resistance to closure followed by increasingly hard resistance to further closure and wherein ease of assembly or disassembly is attained while preventing rotation of the buffer head relative to the casing during use and wherein the means by which such object is attained is not complicated or expensive to manufacture.

Accordingly, an object of the invention is to provide in a shock absorbing mechanism for railway cars, the combination with a tubular casing having an open end and inwardly projecting transverse lugs integral with the casing at said open end; of a tubular open-ended buffer head movably telescoped over the open end of said casing, a front wall closing the other end of said head, a boss on said front wall projecting toward the open end of said head, a seat on said boss, lugs extending laterally from said boss; friction shoes within said casing and slidable interiorly therealong; a wedge block engageable with said shoes, an opening in said wedge block, a plurality of lugs extending outwardly from said wedge block and engageable with the casing lugs, other lugs extend- United States Patemof said wedge block opening; and resilient elements housed within the casing respectively resisting movement inwardly of the casing of the shoes and of the retainer key.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiments thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application as indicated in the appended claims.

"of this invention comprises an end cap A telescopically movable about the open'end of a cylinder or casing B having a wedge block C biased outwardly thereof by resilient means D which reacts againstfriction shoes E in contact with the wedge C. A lockingmeans F inter- Patented May 2, 1961 connects the end cap A and the wedge block C to prevent rotation of these two members relative to each other when the mechanism is in assembled and operable condition. f

From Figure l of the drawings,it will be seen that the cylinder or casing B is of substantially tubular cross section having an open end and having an integral rear wall 10 closing the other end. Flanges 12 extending laterally from said rear wall 10 provide means for securing the cylinder in an appropriate position upon a railway car in a conventional manner such as by bolts or rivets (not shown) extending through the holes 14. The tubular side wall 16 extends away from the rear wall 10 and is provided with internal spring guide ribs 18 adjacent to the rear wall 10 serving to center the resilient means D which comprises inner and outer coil springs 19 and 21. In the vicinity of the open end of the cylinder, as at 20, the side wall 16 assumes a hexagonal interior configuration, and is substantially thickenedto provide an interior tapered friction surface 22. This thickened wall portion 20 presents three V-shaped interior friction surfaces 22', tapering inwardly from the open end of the cylinder toward the central longitudinal axis of the cylinder.

The cap A is provided with a tubular wall 24 telescopically slidable or movable over the end of the cylinder adjacent to the open end thereof. 9 into a circular front wall 26 which constitutes the bufiing surface proper and which has a convex outer face usual in shock absorbing mechanisms of this type.

The wedge or wedge block C is in the form of a hollow block havinglat'erally and outwardly extending lugs faces 33 on the friction shoes E which contact and are outwardly biased by the spring 21.

At the front end of the wedge block C, laterally extending lugs 34 project inwardly and engage lateral lugs 38 extending outwardly from a boss 36 which depends from and is integral with the front wall 26 of the cap A. As can be seen from Figure 1, the end cap A has a lost motion connection with the wedge block C because the distance between the front wall 36 and the lugs 38 is greater than the longitudinal dimension or thickness of the lugs 34 and because of the clearance provided between the lugs 38 and the interior bottom surface of the wedge block C. This lost motion connection permits the end cap A to move toward the casing under the sole resistanceof the inner spring 19 during initial closure unaffected by the high resistance to closure subsequently generated by the friction clutch when the wall 26 contacts and moves the wedge block C. The boss 36 is recessed as at 40 for the reception of a retainer or locking key 42, the shank 44 of which extends within the recess 40 and likewise extends through a bore or opening 46 provided in the wedge C. The locking key 42 terminates at its other or rear end in an enlarged head 48 in contact with inner spring 19 and having a T-slot 50 for the reception of a tool (not shown)) which can be passed througha hole 52 in the rear wall 10, through the center of spring 19 and into the T-slot 50, and then rotated about 90 degrees for the purpose of compressing the inner spring 19 during assembly or disassembly as described hereinafter. The recess 40 in the boss 36 and the bore 46 in the wedge are of a configuration not only complementary to the exterior configuration of the shank 44 of the locking key but also of such shape as to prevent rotation of the cap A relative to the wedge C when the lock- Wall 24 merges ing key F is seated in assembled position as shown in Figure l. A hexagonal recess in the boss 36 with a corresponding hexagonal bore 46 in the wedge and a hexagonal shank 44 as clearly shown in Figure 3 of the draw ings is an entirely suitable configuration. It 'will be apparent, however, that a hexagonal configuration is only exemplary and that other configurations can be used for the purpose intended.

Figure 4 shows a locking key 42 made in two parts. The shank 44' is separate and distinct from the head 48. A conical head portion 54 is formed on an end of the shank 44 and an indented conical seat 56 is provided in the head 48 of the retaining key 42'. In other respects, the key 42' is similar to the key shown in Figure 3.

The resilient means D, shown as comprising a pair of nested coil springs 19 and 21, is under an initial compression and is disposed within the cylinder B so that the outer spring 21 has its forward end bearing against the shoes E and its other end bearing directly against the rear wall 10. The spring 19 is disposed to have its forward end bearing against the head of the locking key 42, thus allowing initial movement of the cap A to take place before such cap contacts and actuates movement of the wedge C. This initial movement is resisted only by the spring 19 as is desirable in bufiing mechanisms of this type since it provides a relatively soft shock absorbing action when small impact forces are transmitted to the mechanism. However, when impact forces are encountered of a magnitude utilizing all of the initial movement, then the friction elements (wedge C, shoes E, friction surfaces 22), together with outer spring 21, enter into shock absorbing operation.

To assemble the shock absorbing mechanism of this invention, shown in Figures 1, 2 and 3, the cylinder B is placed with its open end uppermost, the double coil springs 19 and 21 are placed within the cylinder B, followed by placement of the shoes E and the locking key 42 upon such springs in the upper portion of the cylinder. The wedge C is then placed in position by passing the locking key 42 through the central bore 46 in the Wedge until the wedge rests with its lugs 28 in contact with the upper portions of the shoes E. An assembly tool, not shown, consisting of a ring of greater inside diameter than the wedge C and having depending fingers designed to contact the top surfaces of the shoes E and straddle the lugs 28 of the wedge is then used to depress the shoes against the resistance of spring 21. After the shoes B have been "displaced a sufficient distance rearwardly, the wedge C is depressed rearwardly and rotated approximately thirty degrees so that the wedge lugs 28 register beneath the cylinder lugs 30. Pressure on the assembly tool is then released and the shoes E, under the bias of spring 21, return to their assembled position, as shown in Figure l.

A tool (not shown) having a T-head at one end is then inserted through the hole 52 in the rear wall end of the cylinder housing B and into the T-slot 50 in the head 48 of the locking key 42. This tool is rotated ninety degrees to effect engagement with the interior shoulders of the T-slot 50 and is then drawn rearwardly, and held in such position, to compress the inner spring 19 and depress the locking key within the bore 46 in the wedge, such movement of the key 42 being approximately onehalf its length. The cap A is placed over the front end of the cylinder B so that the lugs 38 on the boss 36 pass between and below the lugs 34 provided on the wedge C. The cap A is then rotated until the respective lugs on the boss 36 and on the wedge C are in registry with each other. At this point the depressing force applied to the T-shaped tool is releasing and this tool removed, permitting the spring 19 to bias the locking key 42 upwardly until the shank 44 of the key is fitted or seated within the hexagonal recess 40 in the boss 36.

In connection with the foregoing assembly procedure, when a locking key 42 is used, such as the one shown in Figure 3, some inconvenience may be encountered in depressing and rotating the wedge C to obtain locking engagement of .thewedge lugs 28 with the cylinder lpgs 3t}. This difficulty is due to the fact that at all times during such rotation the locking key 42 extends through the hexagonal bore 46 in the wedge C and any rotation irnparted to the wedge is resisted by the frictional contact between the head 48 of the key and the inner spring 19. To minimize this resistance a two-part retaining key 42', as shown in Figure 4, can be used. In all'respects the assembly procedure is the same as already described except that less rotational force is required to rotate the wedge to its assembled position. The smaller bearing surface provided by the conical seat 56 and conical head 54 facilitates rotation of the Wedge by minimizing the area of frictional contact. The locking key 42 is moved rearwardly for approximately half the length of its shank 44, the T-shaped tool being used to compress the inner coil spring 19 so that the separate shank 44' falls by gravity as soon as the head 48' is depressed, thus afford ing clearance between the end of the shank 44' and the hexagonal recess 40 of the cap, and permitting the cap A to be placed about the cylinder and rotated to the degree necessary for engagement of the lugs 34 and 38. Thereafter, removal of the T-shaped tool permits the inner spring 19 to forwardly bias the head 48 and in turn seat the shank 44' into assembled position within the re cess 40 while extending within the bore 46 in the wedge.

From the foregoing, it will be appreciated that this invention affords a shock absorbing mechanism having an initial soft spring action during the initial travel of the cap rearwardly toward the cylinder and that thereafter high frictional resistance due to the wedge, shoes and friction surfaces in the casing is encountered. Either of the retaining or locking key arrangements affords a simple structure for assembling and maintaining such assembly in operating condition, or for disassembly if required.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a shock absorbing mechanism for railway cars, the combination with a tubular casing having an open end and laterally projecting integral lugs at said open end, of friction shoes within said casing and slidable interiorly therealong; a wedge block in engagement with said shoes, an opening extending longitudinally through said wedge block, a first set of lugs extending laterally from said wedge block and engageable with said casing lugs to limit movement of said wedge block outwardly of the casing, and a second set of laterally extending lugs on said wedge block; a tubular open-ended end cap movably telescoped over the open end of said casing, a front wall closing the other end of said end cap, a boss on said front wall projecting toward the open end of said cap, a recess in said boss, a set of lugs extending laterally from said boss and longitudinally spaced from said front wall and engageable with said second set of wedge block lugs to limit movement of said end cap outwardly of said casing, the longitudinal distance between said front wall of the end cap and said boss lugs being greater than the longitudinal dimension of the lugs of said second set of wedge block lugs; a retainer key disposed in said wedge block opening and in said recess in said boss, the recess in said boss. the opening in said wedge block and at least a portion of said key being of a configuration preventing rotation of said key relative to said boss and to said wedge block; and a pair of nested resilient elements housed within the casing, the inner element being in direct engagement with said retainer key and the outer element engaging said shoes.

2. In a shock absorbing mechanism for railway cars, the combination with a'casing having an open end, a rear wall at the other end and inwardly laterally projecting lugs at said open end of the casing; of a butter head movably telescoped over the friction casing, a centrally positioned boss on said head projecting inwardly thereof, a recess in said boss, lugs extending laterally outwardly from said boss; a tapered friction bore in said casing and friction shoes slidable along such bore; a wedge block in Wedging engagement with said shoes, a central longitudinally extending opening in said wedge block, a set of lateral lugs extending outwardly from said wedge block engageable with said casing lugs, another set of lateral lugs extending inwardly. of said wedge block engageable with said boss lugs; a retainer key, a head portion on said key, a shank portion of said key disposed in the opening in said wedge block and in the recess in said boss, said shank portion and the recess and the wedge block opening being of a configuration preventing rotation of said shank portion relative to said recess and said wedge block opening; the longitudinal distance between the front wall and the lugs extending from the boss being greater than the longitudinal dimension of said other set of wedge block lugs; and a pair of nested springs, each of which resisting longitudinal inward movement of the shoes and of the head of said retainer key, respectively.

3. A shock absorbing mechanism according to claim 1 in which the retainer key consists of two separable portions engageable with each other.

4. A shock absorbing mechanism according to claim 3 in which one of the retainer key portions is provided with a seat and the other portion of said retainer key is provided with a complementary surface engageable with said seat and permitting rotation of one of said portions relative to the other. 7

5. A shock absorbing mechanism according to claim 4 in which the portions of the separable retainer key en gageable with each other are of conical mating configuration.

References Cited in the file of this patent UNITED STATES PATENTS 2,430,505 Haseltine Nov. 11, 1947 2,431,376 Dath Nov. 25, 1947 2,532,013 Dath Nov. 28, 1950 2,810,485 Housman Oct. 22, 1957 

